explain select i_item_id, avg(ss_quantity) agg1, avg(ss_list_price) agg2, avg(ss_coupon_amt) agg3, avg(ss_sales_price) agg4 from store_sales, customer_demographics, date_dim, item, promotion where store_sales.ss_sold_date_sk = date_dim.d_date_sk and store_sales.ss_item_sk = item.i_item_sk and store_sales.ss_cdemo_sk = customer_demographics.cd_demo_sk and store_sales.ss_promo_sk = promotion.p_promo_sk and cd_gender = 'F' and cd_marital_status = 'W' and cd_education_status = 'Primary' and (p_channel_email = 'N' or p_channel_event = 'N') and d_year = 1998 group by i_item_id order by i_item_id limit 100;
